JP5988232B2 - DRIVE CIRCUIT FOR ELECTRIC VEHICLE AND DIAGNOSTIC METHOD FOR DETERMINING EFFECT OF SHORT CIRCUIT TO GROUND VOLTAGE BETWEEN CONTACTOR COIL AND VOLTAGE - Google Patents

Description

The present invention relates to a drive circuit for an electric vehicle and a diagnostic method for determining that a short circuit to ground voltage has appeared between a contactor coil and a voltage drive.
This application claims priority based on U.S. Patent Application No. 13 / 539,850 filed on July 2, 2012, and all the contents disclosed in the specification and drawings of the applicable U.S. application are hereby incorporated by reference. Incorporated into the application.

  The inventor has recognized the need for an improved drive circuit for an electric vehicle and a diagnostic method for determining that a short circuit to ground voltage has appeared between the contactor coil and the voltage drive.

  According to one aspect of the invention, a drive circuit for an electric vehicle is provided. The drive circuit includes a first voltage driver having a first input line and a first output line, wherein the first input line is connected to a microprocessor, and the first output line is connected to one end of a contactor coil of the contactor. Is done. The driving circuit may further include a second voltage driver having a second input line, a second output line, and a second voltage sensing line, the second input line being connected to a microprocessor, and the second output. A line is connected to the other end of the contactor coil, and the second voltage sensing line is connected to the microprocessor. The microprocessor generates a first pulse width modulation signal on the first input line, and the first voltage driver receives a second pulse width modulation signal received at one end of the contactor coil on the first output line. An output is configured to activate the contactor coil. The microprocessor may be configured to repeatedly measure a voltage at one end of the contactor of the contactor to obtain a plurality of first voltage values. Further, the microprocessor determines a filtered first voltage value based on the plurality of first voltage values, repeatedly measures a voltage at the other end of the contact of the contactor, and outputs a plurality of second voltage values. A voltage value is obtained and configured to determine a filtered second voltage value based on the plurality of second voltage values. The microprocessor repeatedly measures the voltage of the second voltage sensing line to obtain a plurality of third voltage values indicating the amount of current flowing through the second voltage driver, and the plurality of third voltages. A filtered first current value is configured to be determined based on the voltage value. The microprocessor may be configured such that the filtered first voltage value is substantially equal to the filtered second voltage value and the filtered first current value is smaller than a critical current value, If it is indicated that a short circuit to the ground voltage appears between the contactor coil and the second voltage driver, the generation of the first pulse width modulation signal is stopped and the contactor coil is deactivated. Composed.

  According to another aspect of the present invention, a method for diagnosing a drive circuit for an electric vehicle is provided. The driving circuit is a driving circuit including a first voltage driving unit, a second voltage driving unit, and a microprocessor. The first voltage driver includes a first input line and a first output line, the first input line is connected to a microprocessor, and the first output line is connected to one end of a contactor coil of the contactor. The second voltage driver includes a second input line, a second output line, and a second voltage sensing line, the second input line is connected to a microprocessor, and the second output line is the other end of the contactor coil. And the second voltage sensing line is connected to the microprocessor. The diagnostic method uses the microprocessor to generate a first pulse width modulation signal on the first input line, and the first voltage driver receives at one end of the contactor coil. Is output to the first output line, and the contactor coil is activated. The diagnostic method may further include a step of repeatedly measuring a voltage at one end of the contactor using the microprocessor to obtain a plurality of first voltage values. The diagnosis method may further include determining a filtered first voltage value based on the plurality of first voltage values using the microprocessor. The diagnostic method may further include a step of repeatedly measuring a voltage at the other end of the contact of the contactor to obtain a plurality of second voltage values using the microprocessor. The diagnosis method may further include determining a filtered second voltage value based on the plurality of second voltage values using the microprocessor. The diagnostic method may repeatedly measure the voltage of the second voltage sensing line using the microprocessor to obtain a plurality of third voltage values indicating the amount of current flowing through the second voltage driver. Further comprising steps. The diagnosis method may further include determining a filtered first current value based on the plurality of third voltage values using the microprocessor. Further, the diagnosis method uses the microprocessor, and the filtered first voltage value is substantially equal to the filtered second voltage value, and the filtered first current value is a critical current. If it is smaller than the value and indicates that a short circuit to the ground voltage appears between the contactor coil and the second voltage driver, the generation of the first pulse width modulation signal is stopped, and the contactor coil Further comprising the step of deactivating.

It is the block diagram which showed the electric vehicle which has a drive circuit by one Embodiment. FIG. 2 is a circuit diagram of a first voltage driving unit used in the driving circuit shown in FIG. 1. FIG. 3 is a circuit diagram of a second voltage driving unit used in the driving circuit shown in FIG. 1. FIG. 2 is a schematic diagram showing a first set of voltage pulses output from the drive circuit of FIG. 1. FIG. 3 is a schematic diagram showing a second set of voltage pulses output from the drive circuit of FIG. 1. FIG. 2 is a schematic diagram illustrating a signal output from a drive circuit in FIG. 1. FIG. 4 is a schematic diagram illustrating a third set of voltage pulses output from the drive circuit of FIG. 1. FIG. 6 is a schematic diagram illustrating a fourth set of voltage pulses output from the drive circuit of FIG. 1. FIG. 5 is a schematic diagram illustrating another signal output from the drive circuit of FIG. 1. FIG. 6 is a schematic diagram illustrating a fifth set of voltage pulses output from the drive circuit of FIG. 1. FIG. 8 is a schematic diagram illustrating a sixth set of voltage pulses output from the drive circuit of FIG. 1. FIG. 6 is a schematic diagram showing still another signal output from the drive circuit of FIG. 1. It is the flowchart which showed the diagnostic method by another embodiment. It is the flowchart which showed the diagnostic method by another embodiment. It is the flowchart which showed the diagnostic method by another embodiment.

  1 to 3 show an electric vehicle 10 including a drive circuit 40 according to an embodiment. The electric vehicle 10 includes a battery pack 30, a main contactor 50, a ground contactor 52, a precharge contactor 54, a current sensor 60, a resistor 70, a high voltage inverter 90, an electric motor 91, electric wires 100, 102, 104, 106, 114, 116, 118, a vehicle controller 117, a current sensor 119, and a power supply 121. The advantage of the drive circuit 40 is that it executes a diagnostic algorithm that determines that a short circuit to ground voltage has appeared between the contactor coil and the voltage drive.

Prior to the description of the structure and operation of the electric vehicle 10, some terms used in this specification will be briefly described.
The “filtered voltage value” means a voltage value determined based on a plurality of voltage values. The filtered voltage value can be determined using a filter equation.
The “filtered current value” means a current value determined based on a plurality of voltage values or a plurality of current values. The filtered current value can be determined using a filter equation.
“Filter equation” means an equation used to calculate a value based on a plurality of values. In an embodiment, the filter equation may consist of a first order lag filter or an integral function. Of course, other types of filter equations known in the field to which the present invention belongs can also be used.
“High voltage” means a voltage higher than a voltage expected during a predetermined operation mode of the driving circuit. For example, assuming that the expected voltage at a given point in the drive circuit is 4V (eg, 12V at a 30% duty cycle) in a given operating mode of the drive circuit, It can be said that the actual voltage of 4.5 V at the predetermined point is a high voltage.
“High logic voltage” means a voltage corresponding to a Boolean logic value “1” in the driving circuit.

The battery pack 30 outputs an operating voltage to a high voltage inverter 90 that outputs an operating voltage to the electric motor 91 via the electric wire 118. The battery pack 30 includes battery modules 140, 142, and 144 that are electrically connected to each other in series.
The drive circuit 40 controls the operation positions of the main contactor 50, the ground contactor 52, and the precharge contactor 54. The driving circuit 40 includes a microprocessor 170, a first voltage driving unit 180, a second voltage driving unit 182, a third voltage driving unit 184, a fourth voltage driving unit 186, a fifth voltage driving unit 188, and a sixth voltage driving. Part 190.

  The microprocessor 170 includes the first voltage driving unit 180, the second voltage driving unit 182, the third voltage driving unit 184, the fourth voltage driving unit 186, the fifth voltage driving unit 188, and the sixth voltage driving unit 188. A control signal for controlling the operation of the voltage driver 190 is generated. The microprocessor 170 executes a software program stored in the memory device 171 in order to execute a diagnostic algorithm which will be described later in connection with the driving circuit 40. The memory device 171 stores software algorithms, values, and status flags. The microprocessor 170 is operably connected to a Vcc voltage source that supplies an operating voltage (eg, 5V) to the microprocessor 170.

Before describing a diagnostic algorithm associated with the driving circuit 40 according to an embodiment, the structure and operation of the driving circuit 40 will be described.
Referring to FIGS. 1 and 2, the first voltage driver 180 and the second voltage driver 182 activate the main contactor coil 502 to bring the contact point 500 into a closed operation position. And is used to deactivate the main contactor coil 502 to bring the contact 500 into an open operational position.

  Referring to FIGS. 1, 4 to 6, during operation, the microprocessor 170 transmits an initial voltage pulse 602 and a first signal 702 to the input lines 202 and 262 of the first and second voltage drivers 180 and 182. , The voltage driving units 180 and 182 activate the main contactor coil 502 in order to place the contact point 500 in the closed operation position. In particular, if the first voltage driver 180 receives the initial voltage pulse 602, the first voltage driver 180 outputs an initial voltage pulse 652 that activates the main contactor coil 502 in response to the initial voltage pulse 602. .

After generating the initial voltage pulse 602, the microprocessor 170 outputs a pulse width modulated signal 603 having voltage pulses 604, 606, 608, 610 having a duty cycle of about 30%. Of course, the duty cycle of the voltage pulses 604, 606, 608, 610 may be 30% or more, or less than 30%.
Further, after generating the initial voltage pulse 602, the microprocessor 170 continues to output the first signal 702 having a high logic voltage while generating the voltage pulses 604, 606, 608, 610. The first signal 702 turns on the transistor 280 of the second voltage driver 182.

In particular, if the first voltage driver 180 receives the pulse width modulation signal 603, the first voltage driver 180 responds to the pulse width modulation signal 603 in order to maintain the activation of the main contactor coil 502. A signal 653 (see FIG. 5) is output. The pulse width modulation signal 653 has voltage pulses 654, 656, 658, 660 having a duty cycle of about 30%. Of course, the duty cycle of the voltage pulses 654, 656, 658, 660 may be 30% or more, or less than 30%.
If the microprocessor 170 stops outputting the pulse width modulation signal 603 and the first signal 702 to the input lines 202 and 262 of the first and second voltage drivers 180 and 182, respectively, the first and second The second voltage driving units 180 and 182 deactivate the main contactor coil 502 to guide the contact point 500 to the open operation position.

  Referring to FIGS. 1 and 2, the first voltage driver 180 includes a driving circuit 201, an input line 202, an output line 204, and a voltage sensing line 206. The input line 202 is connected to the microprocessor 170 and the driving circuit 201. The output line 204 is electrically connected to one end of the main contactor coil 502. The voltage sensing line 206 is connected to the output line 204 and the microprocessor 170.

  In one embodiment, the driving circuit 201 includes transistors 220 and 222. The transistor 220 includes (i) a base B connected to a node 230 connected to the microprocessor 170, (ii) a collector C connected to the power supply 121 through power supply lines 207 and 209, and ( iii) having an emitter E connected to a node 232 connected to the output line 204; The current sensor 119 is connected in series to the power supply lines 207 and 209, and generates a signal when the power supply 121 supplies a current amount larger than a critical current level to the power supply line 207. A signal generated from the current sensor 119 is received by the microprocessor 170.

  The transistor 222 includes (i) a base B connected to a node 230 connected to the microprocessor 170, (ii) a collector C connected to ground, and (iii) a node 232 connected to the output line 204. And an emitter E connected to the. When the microprocessor 170 applies a high logic voltage to the node 230, the transistor 220 is turned on, the transistor 222 is turned off, and the voltage (eg, 12V) from the power supply 121 is applied to the node 232 and the output. The voltage applied to the line 204 and the voltage applied to the output line 204 is applied to one end of the main contactor coil 502. Conversely, if the microprocessor 170 stops applying high logic voltage to the node 230, the transistor 220 is turned off, the transistor 222 is turned on, and a ground voltage is applied to the node 232 and the output line 204. The ground voltage applied to the output line 204 is applied to one end of the main contactor coil 502.

  Referring to FIGS. 1 and 3, the second voltage driver 182 includes a driving circuit 261, an input line 262, an output line 264, a voltage sensing line 266, and a voltage sensing line 268. The input line 262 is connected to the microprocessor 170 and the driving circuit 261. The output line 264 is electrically connected to the other end of the main contactor coil 502. The voltage sensing line 266 is connected to the output line 264 and the microprocessor 170. When the main contactor coil 502 is activated, the voltage sensing line 268 receives a voltage indicating a first current of the main contactor coil 502 and connects to the microprocessor 170.

  In one embodiment, the driving circuit 261 includes a transistor 280 and a resistor 282. The transistor 280 includes (i) a gate G connected to the microprocessor 170, (ii) a drain D connected to the node 284 connected to the voltage sensing line 266 and the output line 264, and (iii) a resistor. Having a source S connected to 282. The resistor 282 is connected between the source S and electrical ground. A node 286 at one end of the resistor 282 is connected to the microprocessor 170 via the voltage sensing line 268. When the microprocessor 170 applies a high logic voltage to the gate G, the transistor 280 is turned on, and a current flows from the main contactor coil 502 to the ground through the transistor 280 and the resistor 282. Conversely, when the microprocessor 170 stops applying the high logic voltage to the gate G, the transistor 280 is turned off, and current flows through the main contactor coil 502, the transistor 280, and the resistor 282. Do not allow that.

  Referring to FIG. 1, the third voltage driver 184 and the fourth voltage driver 186 activate the ground contactor coil 512 and open the contact 510 in order to place the contact 510 in a closed operation position. Used to deactivate the ground contactor coil 512 for positioning.

  Referring to FIGS. 1 and 7 to 9, during operation, the microprocessor 170 transmits an initial voltage pulse 802 and the first signal 902 to the input lines 302 of the third and fourth voltage drivers 184 and 186. , 362 respectively, the voltage driving units 184 and 186 activate the ground contactor coil 512 in order to place the contact point 510 in the closed operation position. In particular, if the third voltage driver 184 receives the initial voltage pulse 802, the third voltage driver 184 outputs an initial voltage pulse 852 that activates the ground contactor coil 512 in response thereto. .

After generating the initial voltage pulse 802, the microprocessor 170 outputs a pulse width modulated signal 803 having voltage pulses 804, 806, 808, 810 having a duty cycle of about 30%. Of course, the duty cycle of the voltage pulses 804, 806, 808, 810 may be 30% or more, or less than 30%.
Further, after generating the initial voltage pulse 802, during the generation of the voltage pulses 804, 806, 808, 810, the microprocessor 170 includes a transistor 280 included in the fourth voltage driver 186. In order to continuously turn on the transistor, the first signal 902 having a high logic voltage is continuously output.

In particular, when the third voltage driver 184 receives the pulse width modulation signal 803, the third voltage driver 184 activates the ground contactor coil 512 in response thereto. (See FIG. 8). The pulse width modulation signal 853 includes voltage pulses 854, 856, 858, and 860 having a duty cycle of 30%. Of course, the duty cycle of the voltage pulses 854, 856, 858, 860 may be 30% or more, or less than 30%.
If the microprocessor 170 stops outputting the pulse width modulation signal 803 and the first signal 902 to the input lines 302 and 362 of the third and fourth voltage drivers 184 and 186, respectively, the voltage drive Portions 184 and 186 deactivate the ground contactor coil 512 to place the contact 510 in the open position.

  Referring to FIGS. 1 and 2, the third voltage driver 184 includes a driving circuit 301, an input line 302, an output line 304, and a voltage sensing line 306. The input line 302 is connected to the microprocessor 170 and the driving circuit 301. The output line 304 is electrically connected to one end of the ground contactor coil 512. The voltage sensing line 306 is connected to the output line 304 and the microprocessor 170. In one embodiment, the structure of the driving circuit 301 is the same as the structure of the driving circuit 201 described above. Further, the driving circuit 301 includes first power supply lines (not shown), current sensors (not shown), and second power supply lines (not shown) connected in series. Via the power supply 121.

  Referring to FIGS. 1 and 3, the fourth voltage driver 186 includes a driving circuit 361, an input line 362, an output line 364, a voltage sensing line 366, and a voltage sensing line 368. The input line 362 is connected to the microprocessor 170 and the driving circuit 361. The output line 364 is electrically connected to the other end of the ground contactor coil 512. The voltage sensing line 366 is connected to the output line 364 and the microprocessor 170. When the ground contactor coil 512 is activated, the voltage sensing line 368 receives a signal indicating a second current flowing through the ground contactor coil 512 and connects to the microprocessor 170. In one embodiment, the structure of the driving circuit 361 is the same as the structure of the driving circuit 261 described above.

  The fifth voltage driver 188 and the sixth voltage driver 190 activate the precharge contactor coil 522 in order to place the contact 520 in the closed operation position and the precharge contactor coil 522 in order to place the contact 520 in the open operation position. Used to deactivate the charge contactor coil 522.

  Referring to FIGS. 1 and 10 to 12, during operation, the microprocessor 170 transmits an initial voltage pulse 1002 and a first signal 1102 to the input lines 402, 190 of the fifth and sixth voltage drivers 188 and 190. When output to 462, the voltage driving units 188 and 190 activate the precharge contactor coil 522 in order to place the contact 520 in the closed operation position. In particular, if the fifth voltage driver 188 receives the initial voltage pulse 1002, in response thereto, the fifth voltage driver 188 outputs an initial voltage pulse 1052 that activates the ground contactor coil 512. .

After generating the initial voltage pulse 1002, the microprocessor 170 outputs a pulse width modulated signal 1003 having voltage pulses 1004, 1006, 1008, 1010 with a duty cycle of about 30%. Of course, the duty cycle of the voltage pulses 1004, 1006, 1008, 1010 may be 30% or more, or less than 30%.
Further, after the initial voltage pulse 1002 is generated and the voltage pulses 1004, 1006, 1008, and 1010 are output, the microprocessor 170 includes a transistor 280 included in the sixth voltage driver 190. To continuously turn on the transistor, the first signal 1102 having a high logic voltage is continuously output.

When the fifth voltage driver 188 receives the pulse width modulation signal 1003, the fifth voltage driver 188 outputs a pulse width modulation signal 1053 that activates the precharge contactor coil 522 in response to the reception. To do. The pulse width modulation signal 1053 includes voltage pulses 1054, 1056, 1058, 1060 having a duty cycle of 30%. Of course, the duty cycle of the voltage pulses 1054, 1056, 1058, 1060 may be 30% or more, or less than 30%.
If the microprocessor 170 stops outputting the pulse width modulation signal 1003 and the first signal 1102 to the input lines 402 and 462 of the fifth and sixth voltage drivers 188 and 190, respectively, the voltage drive Portions 188 and 190 deactivate the precharge contactor coil 522 to place the contact 520 in the open position.

  The fifth voltage driver 188 includes a driving circuit 401, an input line 402, an output line 404, and a voltage sensing line 406. The input line 402 is connected to the microprocessor 170 and the driving circuit 401. The output line 404 is electrically connected to one end of the precharge contactor coil 522. The voltage sensing line 406 is connected to the output line 404 and the microprocessor 170. In one embodiment, the structure of the driving circuit 401 is the same as the structure of the driving circuit 201 described above. Further, the driving circuit 401 includes a first power supply line (not shown), a current sensor (not shown), and a second power supply line (not shown) connected in series. Via the power supply 121.

  The sixth voltage driver 190 includes a driving circuit 461, an input line 462, an output line 464, a voltage sensing line 466, and a voltage sensing line 468. The input line 462 is connected to the microprocessor 170 and the driving circuit 461. The output line 464 is electrically connected to the other end of the precharge contactor coil 522. The voltage sensing line 466 is connected to the output line 464 and the microprocessor 170. When the precharge contactor coil 522 is activated, the voltage sensing line 468 receives a signal indicating a second current flowing through the precharge contactor coil 522 and connects it to the microprocessor 170. In one embodiment, the structure of the driving circuit 461 is the same as the structure of the driving circuit 261 described above.

  The main contactor 50 is electrically connected in series to the battery pack 30, the current sensor 60, and the inverter 90. In particular, the positive terminal of the battery pack is electrically connected to the current sensor 60 through the electric wire 100. The current sensor 60 is electrically connected to one end of the contact 500 of the main contactor 50 through the electric wire 102. The other end of the contact 500 is electrically connected to the inverter 90 through the electric wire 106. When the main contactor coil 502 is activated, the contact 500 is in a closed operation position, and the positive terminal of the battery pack 30 and the inverter 90 are electrically connected. When the main contactor coil 502 is deactivated, the contact 500 is in the open operation position, and the positive terminal of the battery pack 30 is electrically separated from the inverter 90.

  The ground contactor 52 is electrically connected in series between the battery pack 30 and the inverter 90. The negative terminal of the battery pack 30 is electrically connected to one end of the contact 510 of the ground contactor 52 through the electric wire 114. The other end of the contact 510 is electrically connected to the inverter 90 through the electric wire 116. When the ground contactor coil 512 is activated, the contact 510 is in a closed operation position, and the negative terminal of the battery pack 30 and the inverter 90 are electrically connected. When the ground contactor coil 512 is deactivated, the contact 510 is in the open operation position, and the negative terminal of the battery pack 30 is electrically separated from the inverter 90.

  The precharge contactor 54 is electrically connected to the main contactor 50 in parallel. One end of the contact 520 is electrically connected to the electric wire 102 through the electric wire 104. The other end of the contact 520 is electrically connected to the electric wire 106 via the resistor 70 and the electric wire 108. When the precharge contactor coil 522 is activated, the contact 520 is in a closed operation position, and the positive terminal of the battery pack 30 is electrically connected to the inverter 90. When the precharge contactor coil 522 is deactivated, the contact 520 is in the open operation position, and the positive terminal of the battery pack 30 is electrically separated from the inverter 90.

  The current sensor 60 generates a signal indicating the total amount of current supplied from the battery pack 30 to the inverter 90. The microprocessor 170 receives the signal from the current sensor 60. The current sensor 60 is electrically connected in series between the positive terminal of the battery pack 30 and one end of the contact 500.

  Referring to FIGS. 1, 4 to 6, and 13 to 15, when at least one of the main contactor coil 502, the ground contactor coil 512, and the precharge contactor coil 522 is activated, A flow diagram illustrating a diagnostic method for the drive circuit 40 of the electric vehicle 10 will be described. The diagnostic method determines that a short circuit to ground voltage has appeared between the contactor coil and the voltage driver. For the sake of brevity, a diagnosis method for controlling the main contactor coil 502 will be described with reference to the main contactor coil 502, the first voltage driving unit 180, and the second voltage driving unit 182. . It should be understood that the following diagnosis method can also be applied to the ground contactor coil 512 and / or the precharge contactor coil 522 and a drive circuit including them.

  In step 1300, the electric vehicle 10 uses the driving circuit 40 including the first voltage driving unit 180, the second voltage driving unit 182, a current sensor 119, and the microprocessor 170. The first voltage driver 180 includes the first input line 202, the first output line 204, and a power supply line 207. The first input line 202 is connected to the microprocessor 170. The first output line 204 is connected to one end of the contactor coil 502 of the contactor 50. The current sensor 119 is electrically connected to the power supply line 207. The second voltage driver 182 includes the second input line 262, the second output line 264, and the second voltage sensing line 268. The second input line 262 is connected to the microprocessor 170. The second output line 264 is connected to the other end of the contactor coil 502. The second voltage sensing line 268 is connected to the microprocessor 170. After step 1300, the process proceeds to step 1302.

In step 1302, the microprocessor 170 generates a first pulse width modulation signal 603 on the input line 202, and receives a second pulse width modulation signal 653 received at one end of the contactor coil 502 in the first voltage driver. The contactor coil 502 is activated by causing 180 to output to the output line 204. After step 1302, the process proceeds to step 1304.
In step 1304, while the second voltage driver 182 generates a first pulse width modulation signal to receive current from the contactor coil 502 of the output line 264 to activate the contactor coil 502, the microprocessor 170 outputs a first signal 702 to the input line 262. After step 1304, the process proceeds to step 1306.

In step 1306, the current sensor 119 determines whether or not the amount of current flowing through the power supply line 207 is greater than a critical current level. If “Yes”, the process proceeds to step 1320, and “No” is determined. If there is, the process proceeds to step 1322.
In step 1320, the current sensor 119 generates a first signal indicating that the amount of current flowing through the power supply line 207 is greater than a critical current level. The first signal is received by the microprocessor 170. After step 1320, proceed to step 1322.
If the value in step 1306 is “NO”, the process proceeds to step 1322. In step 1322, the microprocessor 170 repeatedly measures the voltage at one end of the contact 500 with the main contactor 50 to obtain a plurality of first voltage values. After step 1322, the process proceeds to step 1324.

In step 1324, the microprocessor 170 determines a filtered first voltage value based on the plurality of first voltage values. In one embodiment, the first filter equation is a first order lag filter equation. For example, the first filter equation according to one embodiment is:
Filtered first voltage value = filtered first voltage value _old + (one voltage value of the plurality of first voltage values−filtered first voltage value _old ) × gain _calibration
It is obvious that the above equation is repeatedly calculated using each voltage value included in the plurality of first voltage values.

In operation 1326, the microprocessor 170 repeatedly measures the other voltage of the contact 500 with the main contactor 50 to obtain a plurality of second voltage values. Stage 1326 may be performed substantially simultaneously with stage 1322. After step 1326, proceed to step 1328.
In step 1328, the microprocessor 170 determines a filtered second voltage value based on the plurality of second voltage values. In one embodiment, the second filter equation is a first order lag filter equation. For example, the second filter equation according to one embodiment is:
Filtered second voltage value = filtered second voltage value _old + (one voltage value of the plurality of second voltage values−filtered second voltage value _old ) × gain _calibration
It is obvious that the above equation is repeatedly calculated using each voltage value included in the plurality of second voltage values.

In step 1330, the microprocessor 170 repeatedly measures the voltage of the second voltage sensing line 268 to obtain a plurality of third voltage values indicating the amount of current flowing through the second voltage driver 182. Stage 1330 may be performed substantially simultaneously with stage 1326. After step 1330, the process proceeds to step 1332.
In step 1332, the microprocessor 170 determines a filtered first current value based on the plurality of third voltage values. In one embodiment, the filtered first current equation is a first order lag filter equation. For example, the filtered first current equation according to one embodiment is:
Filtered first current value = filtered first current value _old + ((one voltage value of a plurality of second voltage values / resistance value of resistor 282) _−filtered first current value _old ) × gain _Calibration
It is obvious that the above equation is repeatedly calculated using each voltage value included in the plurality of second voltage values. The filtered first current value indicates the amount of current flowing through the contactor coil 502. After step 1332, proceed to step 1340.

In operation 1340, the microprocessor 170 determines a difference value based on the filtered first voltage value and the filtered second voltage value. In one embodiment, the difference value is calculated by the following equation:
Difference value = filtered first voltage value−filtered second voltage value After stage 1340, the process proceeds to stage 1342.

  In step 1342, the microprocessor 170 receives the first signal from the current sensor 119 and indicates whether or not an overcurrent is supplied to the power supply line 207, and the difference value is predetermined. It is determined whether or not the contact point 500 is greater than the critical value to indicate that the contact point 500 is in the open operation position. Both of the two conditions further indicate that a short circuit to the ground voltage has appeared in the first voltage driver 180. The first voltage driver 180 may be directly short-circuited to the ground voltage, or may be indirectly short-circuited to the ground voltage via other components of the driving circuit 40. If the value in step 1342 is “Yes”, the process moves to step 1344, and if “No”, the process moves to step 1346.

In step 1344, the microprocessor 170 stops generating the first pulse width modulation signal 603 and the first signal 702, and deactivates the contactor coil 502. After step 1344, the diagnostic method ends.
If the value in step 1342 is “No”, the process proceeds to step 1346. In step 1346, the microprocessor 170 indicates whether the filtered first voltage value is substantially the same as the filtered second voltage value, indicating that the contact 500 is in the closed operating position; In addition, it is determined whether the filtered first current value is smaller than the critical current value to indicate that a low level current flows through the second voltage driver 182. Both of the above two conditions indicate that a short circuit to the ground voltage appears between the contact 500 and the second voltage driver 182. If the value of step 1346 is “yes”, the process proceeds to step 1348, and if “no”, the diagnostic method ends.
In step 1348, the microprocessor 170 stops generating the first pulse width modulation signal 603 and the first signal 702, and deactivates the contactor coil 502. After step 1348, the diagnostic method ends.

  The drive circuit 40 and the diagnostic method provide significant advantages over other circuits and methods. In particular, the driving circuit 40 and the diagnostic method provide a technical effect of determining that a short circuit to the ground voltage has appeared between the contactor coil and the voltage driving unit.

  At least a part of the above-described diagnostic method is embodied in the form of instructions executable by a computer to perform the method, and may be realized in the form of a computer-readable medium. The computer readable medium may include one or more of hard drive, RAM, flash memory, and other computer readable media known to those skilled in the art. The computer-executable instructions are read and executed by one or more computers or microprocessors, which become devices for performing the method.

  As described above, the present invention has been described by using the limited embodiment. However, the present invention is not limited to this embodiment, and is within the scope of the technical idea of the present invention. Many other variations, modifications, substitutions, or equivalent arrangements are possible for those with ordinary knowledge. While various embodiments of the invention have been described, it should be understood that only some of the embodiments may be included. Accordingly, the present invention should not be construed as limited by the foregoing description.

DESCRIPTION OF SYMBOLS 10 Electric vehicle 30 Battery pack 40 Drive circuit 50 Main contactor 52 Grounding contactor 54 Precharge contactor 60 Current sensor 70 Resistance 90 High voltage inverter 91 Electric motor 100,102,104,106,114,116,118 Electric wire 117 Vehicle control part 119 Current sensor 121 Power supply 140, 142, 144 Battery module 170 Microprocessor 171 Memory device 180 First voltage driver 182 Second voltage driver 184 Third voltage driver 186 Fourth voltage driver 188 Fifth voltage driver 190 Sixth voltage driver 201 Drive circuit of first voltage driver 202 Input line of first voltage driver 204 Output line of first voltage driver 206 Voltage sensing lines 207, 209 of first voltage driver Voltage supply unit power supply lines 220 and 222 First voltage drive unit transistors 230 and 232 First voltage drive unit node 261 Second voltage drive unit drive circuit 262 Second voltage drive unit input line 264 Second voltage drive Output lines 266, 268 Voltage sensing lines 207, 209 of the second voltage driver Power supply line 280 of the second voltage driver 280 Transistors 282 of the second voltage driver 284 Resistors 284, 286 of the second voltage driver Node of driving unit 301 Driving circuit of third voltage driving unit 302 Input line of third voltage driving unit 304 Output line of third voltage driving unit 306 Voltage sensing line of third voltage driving unit 361 Driving circuit of fourth voltage driving unit 362 Input line of the fourth voltage driving unit 364 Output line of the fourth voltage driving unit 366, 368 Fourth voltage driving Voltage sensing line 401 Driving circuit for fifth voltage driving unit 402 Input line for fifth voltage driving unit 404 Output line for fifth voltage driving unit 406 Voltage sensing line for fifth voltage driving unit 461 Driving circuit for sixth voltage driving unit 462 Input line of sixth voltage driver 464 Output line of sixth voltage driver 466, 468 Voltage sensing line of sixth voltage driver 500 Contact 502 Main contactor coil 510 Contact 512 Grounding contactor coil 520 Contact 522 Precharge contactor coil

Claims (10)

A drive circuit for driving one or more contactors that electrically connect a battery and an inverter of an electric vehicle,
A first voltage driver;
A second voltage driver;
Including a microprocessor,
The first voltage driver has a first input line and a first output line, the first input line is connected to the microprocessor, and the first output line is connected to one end of a contactor coil of a contactor,
The second voltage driver includes a second input line, a second output line, and a second voltage sensing line, the second input line is connected to the microprocessor, and the second output line is connected to the contactor coil. Connected to the other end, the second voltage sensing line is connected to the microprocessor;
The microprocessor generates a first pulse width modulation signal on the first input line, and the first voltage driver receives a second pulse width modulation signal received at one end of the contactor coil on the first output line. Configured to activate the contactor coil to output,
The microprocessor is further configured to repeatedly measure a voltage at one end of the contactor contact to obtain a plurality of first voltage values;
The microprocessor is further configured to determine a filtered first voltage value based on the plurality of first voltage values;
The microprocessor is further configured to repeatedly measure a voltage at the other end of the contact of the contactor to obtain a plurality of second voltage values;
The microprocessor is further configured to determine a filtered second voltage value based on the plurality of second voltage values;
The microprocessor is further configured to repeatedly measure the voltage of the second voltage sensing line to obtain a plurality of third voltage values indicating the amount of current flowing through the second voltage driver;
The microprocessor is further configured to determine a filtered first current value indicative of an amount of current flowing through the contactor coil based on the plurality of third voltage values;
The microprocessor determines that the filtered first voltage value is substantially equal to the filtered second voltage value and the filtered first current value is a critical current value during diagnosis of the drive circuit. Is smaller than the contactor coil and indicates that a short circuit to ground voltage has appeared between the contactor coil and the second voltage driver, the generation of the first pulse width modulation signal is stopped, and the contactor coil is A drive circuit further configured to be deactivated.   The microprocessor further outputs a first signal to the second input line, and the second voltage driver receives a current from the contactor coil of the second output line for activating the contactor coil. The drive circuit according to claim 1 configured.   The microprocessor has the first filtered voltage value substantially equal to the filtered second voltage value and the filtered first current value is less than the critical current value. The drive circuit of claim 2, further configured to stop the generation of one signal and deactivate the contactor coil.   The driving circuit according to claim 2, wherein the first signal has a high logic voltage while the first pulse width modulation signal is generated.   The drive circuit of claim 1, wherein the contact has a closed operating position when the filtered first voltage value is substantially equal to the filtered second voltage value. A method of diagnosing a drive circuit that drives one or more contactors that electrically connect a battery and an inverter of an electric vehicle,
The driving circuit includes a first voltage driving unit, a second voltage driving unit, and a microprocessor. The first voltage driving unit includes a first input line and a first output line, and the first input line includes: Connected to the microprocessor, the first output line is connected to one end of a contactor coil of the contactor, and the second voltage driver has a second input line, a second output line, and a second voltage sensing line. The second input line is connected to the microprocessor, the second output line is connected to the other end of the contactor coil, the second voltage sensing line is connected to the microprocessor,
The microprocessor generates a first pulse width modulation signal on the first input line, and the first voltage driver receives a second pulse width modulation signal received at one end of the contactor coil as the first output. Activating the contactor coil to output to a line;
Using the microprocessor to repeatedly measure the voltage at one end of the contactor contact to obtain a plurality of first voltage values;
Using the microprocessor to determine a filtered first voltage value based on the plurality of first voltage values;
Using the microprocessor to repeatedly measure the voltage at the other end of the contactor of the contactor to obtain a plurality of second voltage values;
Using the microprocessor to determine a filtered second voltage value based on the plurality of second voltage values;
Using the microprocessor to repeatedly measure the voltage of the second voltage sensing line to obtain a plurality of third voltage values indicating the amount of current flowing through the second voltage driver;
Using the microprocessor to determine a filtered first current value indicative of an amount of current flowing through the contactor coil based on the plurality of third voltage values;
Using the microprocessor, the filtered first voltage value is substantially equal to the filtered second voltage value, and the filtered first current value is less than a critical current value; Stopping the generation of the first pulse width modulation signal and deactivating the contactor coil when indicating that a short circuit to ground voltage has appeared between the contactor coil and the second voltage driver; and A diagnostic method comprising:   Using the microprocessor, a first signal is output to the second input line, and the second voltage driver receives a current for activating the contactor coil from the contactor coil of the second output line. The diagnostic method according to claim 6, further comprising the step of:   If the filtered first voltage value is substantially equal to the filtered second voltage value and the filtered first current value is less than the critical current value, then using the microprocessor, The diagnostic method according to claim 7, further comprising: stopping generation of the first signal and deactivating the contactor coil.   The diagnostic method according to claim 7, wherein the first signal has a high logic voltage while the first pulse width modulation signal is generated.   The diagnostic method of claim 6, wherein the contact has a closed operating position when the filtered first voltage value is substantially equal to the filtered second voltage value.

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